Solar Hydrogen — A Fuel for Avoiding a Greenhouse Future

By Donella Meadows

–November 23, 1989–

If George Bush were an environmental leader, he would not have blocked an international agreement this month to curtail emissions of greenhouse gases.

He would see that the greenhouse problem is in fact an opportunity — to move beyond fossil fuels, oil spills, air pollution, and enthrallment to the Middle East, toward clean, renewable energy we can tap on our own territory.

If he were at the entrepreneurial edge not only of environmental policy but energy policy (hey, I can dream, can’t I?) he would make this nation a leader in developing the fuels of the future. Chief among those fuels is hydrogen made with the energy of the sun.

The World Resources Institute (WRI) recently released a report by Joan M. Ogden and Robert H. Williams that summarizes the potential of solar hydrogen. It makes clear that solar energy research, especially the technology of amorphous silicon photovoltaic cells, has been making quiet but impressive progress.

Photovoltaic cells generate electricity from sunlight. At present they do so at a cost of 10-11 cents per kilowatt-hour — the peak rate I pay to my electric company here in the expensive Northeast. The way its costs are falling, photovoltaic electricity should be available for 2-3 cents per kilowatt-hour by the year 2000, say Ogden and Williams.

That would make it competitive with other electricity sources, except for one small problem. The sun doesn’t shine all the time. In some places, like the expensive Northeast in November, it hardly shines at all.

That’s where hydrogen comes in, as a way to store and transport solar energy. Photovoltaic electricity can be used to split water into hydrogen and oxygen. The oxygen goes off into the atmosphere. The hydrogen, like natural gas, is shipped through pipelines or compressed into bottles, to be burned when and where it’s needed.

On burning it recombines with oxygen to form water vapor again. It releases no greenhouse gas, no sulfur dioxide, no particulates, ozone, volatile organics, no pollutants at all except some nitrogen oxides (which are formed whenever there’s burning in our nitrogen-rich atmosphere).

As opposed to massive coal or nuclear power plants, which take years to build and billions to finance, photovoltaic hydrogen rigs could be set up quickly in small units. It would make sense to put them mostly in the sunny Southwest. If they were to replace all the oil, gas, and coal now used in America they would cover about one-half of one percent of the U.S. land area, or 7 percent of the desert area. That amounts to about half the state of New Mexico, though, of course, the solar collectors wouldn’t all be in one place. They could go on roofs or abandoned mines, or other already-disturbed spaces.

Solar hydrogen for residential and industrial energy use would be technically easy to arrange. The hard part is portable energy for our vehicles. The hydrogen gas would have to be compressed into cylinders, or, probably a better idea, stored as metal (iron, titanium, or nickel) hydride. The metal in the cylinders can be recharged with hydrogen over and over, for the lifetime of the car. A metal hydride cylinder would take about the same space as a 12 gallon gas tank and would carry enough energy to go 200-300 miles between refuelings — but only if the car is much more efficient than our current gas-guzzlers.

Carmakers already know how to make cars that are efficient and that can burn hydrogen. The best engine for the job would be a stratified-charge injection engine. The company farthest ahead in developing a hydrogen automobile is Daimler-Benz of West Germany. They estimate the final fuel cost at about $2 per gallon of gasoline-equivalent, which sounds expensive to us but not to Europeans. That price would look cheap to us too, if we were charged the full cost of the pollution our cars generate.

Hydrogen fuel would work even better for trucks, buses, trains, and other large vehicles, where the weight and volume of fuel are less problematic. Airplanes would be the most difficult; at the moment no one sees an economical way to power them with hydrogen.

When I was a chemistry student I generated enough hydrogen fires in the lab to be very respectful of this gas. So I was most interested in the section of the WRI report that compares the safety of hydrogen to gasoline and natural gas. They turn out not to be very different; the same precautions would be needed that we take with the fuels that already pervade our world.

Solar hydrogen is not a proven technology. Neither are nuclear energy, coal synthetics, gasohol or any of the other exotic fuels our government has poured millions (in the case of nuclear billions) of dollars into developing. But for some reason the government is blind to this alternative. The U.S.spent $3 million on hydrogen fuel research in 1989. Japan spent $20 million, West Germany $50 million.

If George Bush believed in a free market instead of protecting powerful industries (I’m still dreaming), he’d remove the enormous subsidies of nuclear and fossil energy. He’d include environmental and social costs in the prices of present energy systems. He wouldn’t have to do anything more. With a level playing field, there would be hot competition to develop a fuel that would generate no significant air pollutants and no hazardous wastes, that would be based on simple water, that would be tapped with collectors made from abundant sand, and that would never run out as long as the sun shines.

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About The Donella Meadows Project

The mission of the Donella Meadows Project is to preserve Donella (Dana) H. Meadows’s legacy as an inspiring leader, scholar, writer, and teacher; to manage the intellectual property rights related to Dana’s published work; to provide and maintain a comprehensive and easily accessible archive of her work online, including articles, columns, and letters; to develop new resources and programs that apply her ideas to current issues and make them available to an ever-larger network of students, practitioners, and leaders in social change. Read More

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